Cisco VCO/4K Mechanical Assemblies page 55

Serial port 4 can be configured to use clock signals by the TRXC4 and RTXC4 signal lines.
Jumper JP15 configurations of the clock lines are shown in Figure 10. The module is shipped
without clock lines connected.
connects TRXC4 to Port 4 Pin 15
connects TRXC4 to Port 4 Pin 17
connects TRXC4 to Port 4 Pin 24
Figure 10: Jumper 15 Configuration of Clock Lines, Serial Port 4
JP15
1 3 5 7 9
Hardware Configuration
11
connects RTXC4 to Port 4 Pin 24
connects RTXC4 to Port 4 Pin 17
connects RTXC4 to Port 4 Pin 15
Storage/Control I/O Module 1-15